1. Field of the Invention
This invention relates generally to computer color graphics and, more particularly, to apparatus for processing color graphics information to select colors used in a computer graphics display.
2. Description of the Background
Selecting the colors of a picture to be displayed using computer graphics techniques is an important task in the computer graphics field. This becomes even more important when a video image derived from a video signal source, such as a video tape recorder or video disc player, is first stored in a memory and then subsequently displayed as a still picture using computer graphics techniques. Generally, the video signal image is processed using computer graphics techniques and such processed image data is stored in a memory. It is known to obtain such computer display of a still picture using a so-called color palette that contains a fixed, and usually limited, number of colors used in the display of the color picture. The color palette is really a digital memory unit that retains a limited number of colors used in generating the display. The colors available in the color palette are defined and fixed therein in advance and typically there is only a limited number of colors, for example, sixteen colors are usually defined on a color palette. In other words, in the majority of known color graphics data processing systems, there are only 16 colors available for the color display, and they are defined and fixed beforehand.
In previously proposed color graphics data processing systems, the colors that can be used to display the picture may be selected from a relatively large number of colors that are available independently. In that case then, the colors are selected for use by the operator or user who visually checks the original picture being displayed on the monitor and then selects colors to be used to make up the color palette for display of the still picture using the computer graphics. That is, a time consuming operation must occur in which the computer graphics operator selects the defined colors for the color palette by visual/manual means.
Then, when the user or operator wishes to produce a computer graphics color picture that is substantially equal to the original picture provided from the video signal source, it frequently becomes quite difficult to faithfully reproduce the desired colors using only the sixteen predetermined, fixed colors that have been selected in advance.
On the other hand, according to this known method of selecting and specifying the sixteen colors that are available for use in the color palette, it is possible to reproduce a picture having colors relatively close to the original picture by defining the color palette several times. This repetitive method involves an extremely labor intensive effort on the part of the operator, and it has proven quite difficult for the operator to select the optimum sixteen colors to define the color palette.